1. Field of the Invention
The present invention relates to an image sensor usable in facsimile machines, optical character readers and others.
2. Description of the Related Art
One example of the conventional image sensor is shown in FIG. 1 which is a cross-sectional view of the primary parts of the image sensor, taken along a plane perpendicular to the scan direction. The image sensor comprises a frame 30, a transparent covering (glass covering) 31 mounted on the frame 30 at the open top thereof, a base plate 33 mounted within the frame 30, a light emitting section 32 mounted on the base plate 33, another base plate 35 mounted on the frame 30 at the open bottom thereof, and a light receiving section 34 mounted on the base plate 35. The base plate 33 also supports a resilient member 37 which includes a spring-like element formed therein at the leftward end as viewed in FIG. 1. The resilient member 37 fixedly urges an optical system (rod lens array) 36 against the inner mounting wall 30a of the frame 30. In the conventional image sensor, the glass covering 31 is generally adhered to the top end face 30b of the frame 30 through any adhesive. In such a ease, any excess adhesive may flow onto the outer and/or inner wails of the frame 30 to damage the property of the rod lens array 36 and/or to contaminate the frame 30. In order to overcome such problems, a proposal has been made that the top end face 30b of the frame 30 is provided with a groove 39, as shown in FIG. 2. The groove 39 is filled with an adhesive. However, such an arrangement could not completely prevent some excess adhesive from flowing onto the outer and/or inner walls of the frame 30.